Extension-bit.



W. P. SHEETS.

EXTENSION BIT.

APPLICATION FILED AUG.14, 1916.

1,232,397, Patented July 3, 191?.

H MM

@iii?" WILLIAM P. SHEETS, OF PRINCETON, MISSOURI.

EXTENSION-BIT.

Application filed August 14, 1916.

To all whom it may concern Be it known that 1, WILLIAM P. Snnn'rs, a citizen of the United States, residing at Princeton, in the county of Mercer and State of Missouri, have invented a new and useful Extension-Bit, of which the following is a specification.

This invention relates to extension bits whereby bores of different diameters can be produced, one of the objects of the invention being to provide a bit of this character having two opposed cutters both of which are set simultaneously by simple and ethcient means provided for that purpose.

A further object is to provide a bit of this character which is compabt, durable and easily adjusted and which overcomes side drafts such as caused by the use of a single cutter.

With the foregoing and other objects in view which .will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter de scribed and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings Figure 1 is a front elevation of the bit.

Fig. 2 is a section on line 22 Fig. 1.

Fig. 3 is a front view with the face plate and cutters removed.

Fig. 4 is an elevation of the inner side of one of the face plates.

Fig. 5 is a perspective view of one of the cutters.

Fig. 6 is a section on line 66 Fig. 1.

Referring to the figures by characters of reference 1 designates the shank of the bit, the same being slightly enlarged at one end as shown at 2 and provided with opposed flattened faces 3 and 4 extending up to transverse shoulders 5 formed in the shank and which shoulders have recesses 6. Formed in the shank near its free end is a transverse opening 7 and extending longitudinally of this opening at the center thereof is a revoluble stem 8. A lead screw 9 is provided at the end of the shank and ex- Specification of Letters Patent.

Patented July 3, 1917.

Serial No. 114,849.

tends from a block 10 which is secured to the end of shank 1 by the threaded stem 10 of the lead screw and by a screw 10 Thus a new lead screw can be placed on the shank whenever desired.

Mounted for rotation with the stem 8 is a cog wheel 11 provided at one end with bevel gear 12 formed integral therewith.

Extendingobliquely across the fiat faces of the enlargement 2 close to the free end thereof are undercut retaining ribs 14 adapted to be slidably engaged by the undercut faces of dovetailed tongues 15 formed longitudinally along the back faces of cutting blades 16. The upper edges of these blades are beveled as shown at 17 and formed upon the back of each blade and along said edge is a rack 18 adapted to engage the gear 11. Face plates 19 are arranged upon the faces 3 and 4 of the shank. These face plates have beveled ends 21 which are adapted to lap and be slidably engaged by the beveled edges 17 of the blades 16 so as to cooperate with the ribs 14 to hold the blades 16 against displacement relative to the sides of the shank. As shown particularly in Fig. 1, the blades are inclined and the advancing or active end of each blade has a projecting scoring cutter 22.

By arranging the blades as described they will be held to the sides of the shank and when gear 11 is rotated the two blades will be simultaneously shifted in opposite directions respectively, thus either to increase or reduce the diameter of the tool.

One of the plates 19 has a circular opening 23 the inner end of which is counterbored as at 24 and seated within this counterbore is a disk 25 mounted for rotation and having a bevel gear 26 integral there with and meshing with the bevel gear 12. A boss 27 extends from the disk 25 and is mounted for rotation in the opening 23, this boss being provided with a kerf 28 whereby a screw driver or the like may be used for rotating the gear for causing the gear 11 to shift.

The two plates 19 are held together and to the shank by a screw 29 extending therethrough. An opening 30 is extended through the shank and connects the recesses 6. This opening is normally closed at its ends by extensions 20 on the face plates. Studs 31 are extended inwardly from the extensions 20 and normally meet at the center of the opening 80. The meeting ends of these studs are beveled. Projecting into one side of the shank is a spreading screw 32 adapted when screwed inwardly to wedge between the studs 31 and shift them apart, thus to cause the far ends of the plates 19 to press tightly upon the lapped portions of the blades 16 so as to hold said blades against movement.

In using the tool the screw 32 is partly unscrewed so as to become disengaged from the studs 31. Thus the beveled ends 21 0f the plates 19 will not bind on the bevel edges of the blades 16. Consequently by rotating gear 26 in the manner hereinbefore described, the two blades 16 will be shifted simultaneously in opposite directions until a desired diameter of the bit has been obtained, whereupon the screw 32 can again be forced into engagement with the studs 31 to spread them apart and bind the ends of the plates 19 upon the ends of the blades 16. Should the lead screw become broken or worn it can be easily removed and another substituted therefor. As two blades are provided the bit is balanced and will not produce side drafts. Consequently the tool can be easily used.

If desired, and as shown in Figs. 1 and 3, a center cutter 33 may be formed with block 10 so as to out between the lead screw and the blades 16.

What is claimed is A bit including a shank, oppositely disposed cutting blades slidably mounted upon opposed faces respectively of the shank, means interposed between and engaging the blades for simultaneously shifting them in opposite directions respectively, and means engaging the respective blades for binding them against the shank for holding them against movement, said means including side plates connected to the shank and lapping the blades, and spreading means insertible between the plates to tilt the plates.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature in the presence of two witnesses.

WILLIAM P. SHEETS.

Witnesses:

GEO. T. MULLINAX, A. B. LOWRY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 13.0. 

